God works in all hearts…

Although God is Almighty, He can only work in a heart when He finds readiness or makes it. He works differently in humans than in stones. For this we may take the following illustration: if we bake in one oven three loaves of barley-bread, of rye-bread, and of wheat, we shall find the same heat of the oven affects them differently; when one is well-baked, another will be still raw, and another yet more raw. That is not due to the heat, but to the variety of the materials. Similarly God works in all hearts not alike but in proportion as He finds them prepared and susceptible. If the heart is to be ready for the highest, it must he vacant of all other things. If I wish to write on a white tablet, whatever else is written on the tablet, however noble its purport, is a hindrance to me. If I am to write, I must wipe the tablet clean of everything, and the tablet is most suitable for my purpose when it is blank. Similarly, if God is to write on my heart, everything else must come out of it till it is really sanctified. Only so can God work His highest will, and so the sanctified heart has no outward object at all.
–Meister Eckhart (1260-1328)